If I keep the stock ECU what sort of max power could I be looking at? I'd love to get Megasquirt but cannot justify spending £700 on another ECU if it's not going to make much more than 170hp

Am I being too optimistic with parts?

Cheers

Big crank in 3 rib block is not typical... I'd still look for a 7 rib block. No need for aftermarket rods (except mass savings)... Supertech exhaust valves would be 27.5mm. If you use Supertech springs, then you must use their retainers, and their spring seats... I'd also use their keepers. All those extra bits add cost... a set of Toda springs and your done.

Yeah I know about the crank in that block, I'd just rather not remove my engine and not be able to use the car whilst I'm building the engine is all plus it's a free engine. I have been told it's not typical but it can still take good power through it. Plus it's coming from a very reputable source so I know all is okay with block.

If I keep the stock ECU what sort of max power could I be looking at? I'd love to get Megasquirt but cannot justify spending £700 on another ECU if it's not going to make much more than 170hp

Am I being too optimistic with parts?

Cheers

Big crank in 3 rib block is not typical... I'd still look for a 7 rib block. No need for aftermarket rods (except mass savings)... Supertech exhaust valves would be 27.5mm. If you use Supertech springs, then you must use their retainers, and their spring seats... I'd also use their keepers. All those extra bits add cost... a set of Toda springs and your done.

Hey guys, AE86 and 4AGE newb here trolling for my own build info. I don't want to hijack this thread so if need be I'll move along. But, just in case, I've got an 89' big port and am curious; when you say Toda springs and done, what other components of that build list can be left out?

You do however want to be careful with oversized valves. People often don't realize how much the mass of a valve effects it. Oversized valves will need more spring to controll the added mass. With that said, with those cams and stock redline I suspect you would be fine.

The other thing to ask yourself is if the gains of OS valves will justify the cost. 1mm OS is about all the stock seats can take and that is opening them up to about their limit. Without opening up the valve throat a bigger valve can actually steal power because it's a bigger obstruction to airflow. So the question is whether you want to go with 1mm over and if it's worth the cost of the valves and proper porting or if it's worth going bigger and getting bigger seats installed to make the valves work properly.

familymanit would probably be best if you started a thread as a proper build is really dependent on the relationship of all the parts. With that said, what OST was getting at is that the Supertech springs are designed to work with all their other components that make it rather expensive to do springs. Whereas springs like ours, Toda and many others is they are designed to work with stock retainers and keepers and all that. You can upgrade those if you want but it's not necessary and not a huge benefit especially if you are staying near stock redline. As for what components on that list you should or shouldn't use or what others you may need is definitely an in depth conversation that would probably deserve it's own thread.

You do however want to be careful with oversized valves. People often don't realize how much the mass of a valve effects it. Oversized valves will need more spring to controll the added mass. With that said, with those cams and stock redline I suspect you would be fine.

The other thing to ask yourself is if the gains of OS valves will justify the cost. 1mm OS is about all the stock seats can take and that is opening them up to about their limit. Without opening up the valve throat a bigger valve can actually steal power because it's a bigger obstruction to airflow. So the question is whether you want to go with 1mm over and if it's worth the cost of the valves and proper porting or if it's worth going bigger and getting bigger seats installed to make the valves work properly.

familymanit would probably be best if you started a thread as a proper build is really dependent on the relationship of all the parts. With that said, what OST was getting at is that the Supertech springs are designed to work with all their other components that make it rather expensive to do springs. Whereas springs like ours, Toda and many others is they are designed to work with stock retainers and keepers and all that. You can upgrade those if you want but it's not necessary and not a huge benefit especially if you are staying near stock redline. As for what components on that list you should or shouldn't use or what others you may need is definitely an in depth conversation that would probably deserve it's own thread.

Thanks for the tip of your springs

Obviously not now, but in the future, would we be able to work out some sort of deal with your pistons, valve springs etc? There is a guy who works in Louisiana and the UK throughout the year, so I am using him as my mule to avoid import tax

I was going to have some head work done as well, port matching and to remove all the unnecessary material like I've seen on one of 'oldeskewltoy' threads somewhere. Got a quote for a stage 1 head (need to look into whatever that covers) for £450. Would removing that material to increase the flow aid the standard valves and remove the want to get larger ones?

Alex170984 wrote:I was going to have some head work done as well, port matching and to remove all the unnecessary material like I've seen on one of 'oldeskewltoy' threads somewhere. Got a quote for a stage 1 head (need to look into whatever that covers) for £450. Would removing that material to increase the flow aid the standard valves and remove the want to get larger ones?

£450 - $640 ish... What will they do for that money? My minimum basic port work runs $600, but there are always other costs involved, so ask them specifically what you get for your money.

oldeskewltoy wrote:Big crank in 3 rib block is not typical... I'd still look for a 7 rib block. No need for aftermarket rods (except mass savings)... Supertech exhaust valves would be 27.5mm. If you use Supertech springs, then you must use their retainers, and their spring seats... I'd also use their keepers. All those extra bits add cost... a set of Toda springs and your done.

I have an engine with a 3-rib block, 42mm crank and small port pistons and rods. As long as everything is to spec, you shouldn't have any problems. Agreed that it's not typical, though. If you do plan to use Supertech springs and retainers do not use the keepers that come in the kit! See this thread for more details. Toward the middle of the thread, you'll see how to determine which keepers you have. From what I have seen, early largeport engines have the right keepers (2 heads that I have measured keepers on, anyway.)

Alex170984 wrote:Do you guys know how much a 4AGZE balanced and polished crankshaft is worth?

Cheers

Toyota only ever made 2 crankshafts for ALL 4AGE engines. One crank is 1983-1987, is referred to as the "small" crank because the rod journal is smaller then the crankshaft that came in 1988-1996. ALL 4AGZEs use the later crank, as do all 4AGEs made after 1988.

has it been cut? If it has been cut, I'd keep looking, as the S/C cranks are far more plentiful then earlier cranks

New cranks may still be available, and last I checked they were under $500

Alex170984 wrote:After my wedding at the end of August this year I am to rebuild another engine I'm being given.

That's pretty cool... when I got married all I got was a toaster and a dinner set

Cheers... jondee86

Lol that's a pretty good gift isn't it haha

No you cannot get new cranks in the UK any more. Cheapest refurb I looked at when I damaged the end of mine was £300 plus shipping plus import tax. Ridiculous really. N/A cranks are much easier to get a hold of over here. SC cranks are like gold dust. I was going to offer the chap who said I could have his, £300...he said I could have it for £50 which was a result and no it's not been cut.

Oldeskewltoy I will ask the chap who gave me the cost of the head mods.

Alex170984 wrote:I was going to have some head work done as well, port matching and to remove all the unnecessary material like I've seen on one of 'oldeskewltoy' threads somewhere. Got a quote for a stage 1 head (need to look into whatever that covers) for £450. Would removing that material to increase the flow aid the standard valves and remove the want to get larger ones?

£450 - $640 ish... What will they do for that money? My minimum basic port work runs $600, but there are always other costs involved, so ask them specifically what you get for your money.

"stage 1 is the fully gas-flowed head, with standard size valves, what we do is strip the head, as remove valves and springs, and then head is cleaned and blasted and then the head is fully gas-flowed and then the old valves are cleaned and re-seated back into the head, all we need is the bare head with the valves and the rest we do in the price".

That's what I get for £450 - obviously shaving/machining the head, 3 angled valve job will be extra.

As already said there is no such thing as an NA or SC crank. There is only an early 40mm crank and after about 86/87 the 42mm crank that every 4AGE after that ran.

If you walk into Toyota and ask for a crank for a 1988 MR2 NA and a 1988 MR2 SC they will hand you two identical cranks with two identical part numbers. If you can't actually get a crank for any 4AGE made after 1987 that is truly unfortunate. I can still get them here but shipping and duties would suck.

I know someone in the UK who should be able to get you a used but inspected 42mm crank. He might also be a resource for other parts you need or possibly even with the build it's self. He doesn't really frequent the forums anymore but if you want me to put you in touch with him shoot me an email and I'll get you his info.

I am getting a polished and balanced 42mm crank from my mate for £50 so no issue there nor is an engine builder.

There is an older fellow I know who has built formula atlantic engines in the past and has had high powered n/a corollas built in his garage as well, so I'm in good hands

He's got 3 pistons 82.5mm bore, HG, piston rings, rods that I can have for my build - just need to find out what make of piston it is...apparently they are bought separately, which makes me think it's going to be really rare and expensive...

plugging your #s in to the first one... and I get a DCR around 9.7. That is higher then Skippy... your cranking compression will likely be over 200psi, that will require a very good chamber/piston to minimize detonation. Drop compression back to 11.5 and your DCR goes down to about 9.5... it still needs a good chamber to tolerate there

A lot might mean different things to different people. It should make a notable improvement if you can keep it from detonating. If I had to wager a guess I'd say maybe 10 hp. That compression bump should net you more if you could keep the same max MBT ignition timing but that is a lot of compression for that little cam though and on pump gas I suspect you will have a hard time avoiding detonation. You may get it to work by pulling timing but that will loose some power. On the bright side running on the high side does mean that if you take it to the track or otherwise throw some race gas in it you can get more out of it when you crank the timing. On pump gas you will have to be real careful though with that much compression and especially with those cams.

On the same subject... from one of the most renown race engine builder/designers.....

Darin Morgan wrote:Some the the best engine builders in the world have tackled that problem and the ones I talked to all did it pretty much the same way. They tried to keep the duration small , little overlap and as much valve velocity they could get away with on an endurance/street cam. They then kept bumping up the CR until it melted and backed off a notch. Its still trial and error is what I am trying to say. You can dig around for every calculation in the book and it will help but it wont tell you how. Talk to people who build these types of engines because high performance pump gas engines are tricky. When it comes to making SERIOUS power with pump gas, Air fuel management is your BEST FRIEND don't forget that!!!! EFI will let you do things that Carburetors cant get close to. Chamber heat, cam duration, overlap duration, air fuel management and don't forget chamber/ piston design! OH boy is that important! After talking to Kasse about everything he went through to make power on low octane fuel, I wont touch it with a twenty foot pole. Its very difficult when your trying to make Serious power with 92 octane, making power with 87 octane,,,,, I wouldn't even try it unless you have a lot of time and money.

I also now have the mk1b crank which is in great condition! But i'm faced with having to buy conrods as I won't have any spare for the 42mm crank. I have them in the other engine however.

Are there reliability issues with using the 40/18 rods with uprated 82mm pistons? Or would it be better buying h-beam rods for my 42mm crank?

Cheers

How high do you intend to twist it? As I pointed out in your other thread.... if you keep the rpm levels to 8000 ish( cammed with 264 type or smaller), then the early crank should work fine. As to pistons.... you can get custom piston fitted to your early rods... no big deal. OR if you want to spend a bit more you can have your rods modified in 1 of 2 ways. Version one is to keep the current pin size (18mm), but to add a bushing to the small end of the rod. This will give you a full floating pin. 2nd option is to have the small end of the rod opened to accept a bigger pin. down side to a bigger pin is it must be a fixed pin - not full floating.

Some will argue you need a full floating pin... as a counter argument the first 3+ years of 4AGE engines all came with fixed wrist pins, it wasn't until the development of the 4AGZE, and the advent of the bigger cranks/rods, did they add the full floating pin feature.

Alex170984 wrote:How is it possible to raise the RPM limit on the standard ECU? Mine cuts fuel or ignition off at 7.6k

I've never had to buy conrods before, are they worth it?

Cheers

as already discussed... you have no need for aftermarket rods... they are an expense you can save on (or do without)... especially since you are limited to factory engine management

stock management does pretty much keep you to 7500. That doesn't mean you can't run the cat cams... It just means that @ 7500 the power is still being made, or stated another way.... you will hit 7500rpm before you hit full power.

The left overs of the block, i.e. pistons, rods and crank are all spot on in terms of condition and tolerance. I am not using those conrods so they are being sold with the pistons and crank.

Is there any way of determining the CC of the head? I'm pretty sure like the block it has not been touched, i.e. shaved, so with the height of head, can that shed any light on it? Or do I need an engineer to do a volume test on it?

The head CC is going to determine what thickness my HG needs to be for my final CR which I hope to be around 11.5